Turning Satellite Images Into Disaster-Relief Efforts

We've seen, by now, satellite imagery of the devastation in Japan. (For a particularly chilling illustration, see this New York Times feature.) Satellite photos tell a powerful story, of course. But they also can be used as leverage in relief efforts. A team at Rochester Institute of Technology, together with several other institutions (Harvard, George Mason, and Penn State, among them), are turning satellite photos into actionable data that the Japanese can use in relief efforts.

"The images on NYTimes are really startling, and bring home to lay readers the level of the devastation," RIT's David Messinger tells Fast Company. "But it's not necessarily useful to the actual people on the ground who have to conduct the relief effort. They need to know where to go, where not to go, where are the limits of the devastation—they need to have quantitative measurements."

On the simplest level, of course, a satellite photo can tell you which road to take, and which to avoid. If a picture shows a destroyed bridge, you'll need to find a detour. But the RIT team goes much deeper than that, mining imagery for data used in logistics. For example, a Japanese relief team might know that certain segment of a town lies in rubble. But they might not know the volume of the rubble—just how large a fleet of trucks they'll need to clear away the debris. Using something called Geographic Information Systems software (GIS), researchers can trace lines around a pile of rubble, and the software will instantly tell you the size of the pile. That's simple enough still, but RIT is working with the National Science Foundation to develop automatic processing tools that will extract that information directly, says Messinger, "on a much larger scale and much faster."

Pre- and post-quake imagery makes automation possible. A program could compare and contrast the two images, much as in the NYT slider feature, and could automatically calculate the devastation that way. Other research might enable the automatic detection of rubble, since debris has a random structure, as opposed to the regular orderly grid of the road and buildings in most towns and cities.

The RIT team also is able to infer the level of flooding from a feature unique to satellite data. While most cameras only capture three colors—blue, green, and red—satellite cameras also capture a fourth color, just beyond red, in the near-infrared part of the spectrum. This part of the spectrum can assess vegetation health—it renders blooms in bright red—and also helps show water, which appears as a very dark blue. Using that data, RIT can forward to Japan assessments of which fields are inundated, which are dry, and so on.

The RIT team also flew a LIDAR system over Haiti in the aftermath of the quake there, capturing 3-D data with a laser. They weren't asked to do so in Japan, and at any rate, it would have been hard to fly the tiny twin-engine holding the equipment to the other side of the globe, says Messinger.